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Transferrin‑modifed liposomes triggered with ultrasound to treat HeLa cells
No full textTargeted liposomes are designed to target specific receptors overexpressed on the surfaces of cancer cells. This technique ensures site-specific drug delivery to reduce undesirable side effects while enhancing the efficiency of the encapsulated therapeutics. Upon reaching the tumor site, these liposomes can be triggered to release their content in a controlled manner using ultrasound (US). In this study, drug release from pegylated calcein-loaded liposomes modified with transferrin (Tf) and triggered with US was evaluated. Low-frequency ultrasound at 20-kHz using three different power densities (6.2 mW/cm2, 9 mW/cm2 and 10 mW/cm2) was found to increase calcein release. In addition, transferrin-conjugated pegylated liposomes (Tf-PEG liposomes) were found to be more sonosensitive compared to the non-targeted (control) liposomes. Calcein uptake by HeLa cells was found to be significantly higher with the Tf-PEG liposomes compared to the non-targeted control liposomes. This uptake was further enhanced following the exposure to low-frequency ultrasound (at 35 kHz). These findings show that targeted liposomes triggered with US have promising potential as a safe and effective drug delivery platform.American University of SharjahPatient's Friends Committee-SharjahAl-Jalila FoundationAl Qasimi FoundationTechnology Innovation Pioneer (TIP) Healthcare AwardsDana Gas Endowed Chair for Chemical Engineerin
Two decades of research into SIEs and what do we know? A systematic review of the most influential literature and a proposed research agenda
No full textPurpose. This paper aims: to undertake a systematic literature review on SIEs, examining twenty years of literature published between 2000 and 2020, focusing on the most-cited empirical work in the field; to analyse the topics covered by these studies; and to propose a research agenda.
Methodology. We conducted a systematic literature review, identifying the 20 most-cited empirical articles through citation analysis during the period and, because citations accrue over time, the six most-cited empirical articles of the last three years. We then used content analysis to examine the main themes they address and identify the research gaps.
Findings. The most common themes addressed in the SIE literature are: analysis of the types and distinctions of SIEs, motivation to undertake self-initiated expatriation, SIEs' adjustment to the new country, and SIEs' careers and outcomes.
Originality. This paper provides a first opportunity to look back at 20 years of research into a relatively new topic, highlighting the main research themes and knowledge gaps, and setting directions for future research. The paper expands knowledge on SIEs, assisting SIE scholars and IHRM practitioners to develop a global, critical understanding of SIEs' issues, and hopefully energising future research in this field
Non-Destructive Water Leak Detection Using Multitemporal Infrared Thermography
No full textWaterleakage detection and localization in distribution networks pipelines is a challenge for utility companies. For this purpose, thermal Infrared Radiation (IR) techniques have been widely applied in the literature. However, the classical analysis of IR images has not been robust in detecting and locating leakage, due to presence of thermal anomalies such as shadows. In this study, to improve the detection and location accuracy, a digital image processing tool based on multitemporal IR is proposed. In multitemporal IR analysis, the variation of soil's temperature due to field temperature can be obtained; and hence; estimating variations due to water leakage would be more accurate. An experimental setup was built to evaluate the proposed multitemporal IR water leak detection method. In order to consider the temporal temperature variation due to water leakage and mitigate the field temperature effects, a luminance transformation of the IRimages was introduced. To determine the temporal temperature variation of the soil's surface due to the leakage, several metrics have been considered such as the difference, the ratio, the log-ratio and the coefficient variation (CV) images. Based on the experimental results, the log-ratio and the CVimages were the most robust metrics. Then, based on log-ratio or the CV image, a temporal variation image (TVI) that traduces the temporal IR luminance variation was introduced. The analysis of the TVI image showed that the CV image is less noisy than the log-ratio image, and can more accurately locate the leakage. Finally, based on TVI histogram, a threshold was de ned to classify the TVI image into leakage/non-leakage areas. Results showed that the proposed method is capable of accurately detecting and locating water leakage, which is an improvement to the false detections of spatial thermal IR analysis.American University of SharjahSmart City Research Institut
A Machine Learning Approach to Predicting Diabetes Complications
No full textA Master of Science thesis in Computer Engineering by Yazan Khaled Jian entitled, “A Machine Learning Approach to Predicting Diabetes Complications”, submitted in December 2021. Thesis advisor is Dr. Assim Sagahyroon and thesis co-advisors are Dr. Fadi Aloul and Dr. Michel Pasquier. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).Machine learning and data mining techniques have been widely used over the years to extract knowledge from data. The goal of this thesis is to study several diabetes complications. Diabetes Mellitus (DM) is a chronic disease that is considered to be life threatening. It can affect any part of the body over time resulting in more serious complications such as impacts on eyesight, perception, motor control and more. To study diabetes complications, a dataset collected by the Rashid Centre for Diabetes and Research (RCDR) located in Ajman, UAE was utilized. The dataset consists of 884 records with 79 features and 8 complications. The complications’ set contains metabolic syndrome, dyslipidemia, neuropathy, nephropathy, diabetic foot, hypertension, obesity, and retinopathy. Some essential preprocessing steps were needed to handle the missing values and imbalanced data problems. Moreover, several techniques were used to study the problem in hand. The first part of this thesis focused on generating association rules from the dataset using unsupervised learning techniques. This step was essential to extract valuable knowledge and relations between several attributes in the dataset and helped to develop a better understanding of DM and its complications. For instance, we extracted several rules indicating some possible relations between metabolic syndrome, hypertension and dyslipidemia. Further preprocessing steps were needed such as data discretization. For the second part of the research, different supervised classification algorithms were utilized to build several models to predict and diagnose eight diabetes complications. Furthermore, feature selection was performed to select the top 5 and 10 features for each complication. Repeated stratified k-fold cross validation was employed for a better estimation of the performance with a k=10 and a total of 10 repetitions. Accuracy and F1-score were used to evaluate the models’ performance reaching a maximum of 97.8% and 97.7% for accuracy and F1-scores, respectively.College of EngineeringDepartment of Computer Science and EngineeringMaster of Science in Computer Engineering (MSCoE
Lower Semicontinuity in L¹ of a Class of Functionals Defined on BV with Caratheodory Integrands
No full textWe prove lower semicontinuity in ¹(Ω) for a class of functionals :(Ω) →ℝ of the form ()=∫Ω(, ) + ∫Ω()|Dˢ| where :Ω⨉ℝᴺ→ℝ, Ω⊂ℝᴺ is open and bounded, (.,) ∊ ¹(Ω) for each satisfies the linear growth condition lim|→∞ (,)/|| = () ∊ (Ω) ∩ ∞ (Ω) and is convex in depending only on || for a.e. . Here, we recall for ∊ (Ω); the gradient measure = + (Dˢ)() is decomposed into mutually singular measures and (Dˢ)(). As an example, we use this to prove that ∫Ω() √[²() + | |² + ∫Ω()|Dˢ|] is lower semicontinuous in ¹(Ω) for any bounded continuous and any ∊ ¹(Ω). Under minor addtional assumptions on , we then have the existence of minimizers of functionals to variational problems of the form () + || - ₀||¹ for the given ₀ ∊ ¹(Ω) due to the compactness of (Ω) in ¹(Ω)
Flexural Bond Performance of Anchored CFRP Laminates to Concrete Beams
No full textA Master of Science thesis in Civil Engineering by Ghusoon Subhi Alshami entitled, “Flexural Bond Performance of Anchored CFRP Laminates to Concrete Beams”, submitted in December 2021. Thesis advisor is Dr. Rami Hawileh and thesis co-advisor is Dr. Jamal Abdalla. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).Fiber-reinforced polymer (FRP) composites are being extensively used in retrofitting and strengthening of reinforced concrete (RC) members due to their superior properties such as high strength and corrosion resistance. This form of retrofitting has proven to be effective in enhancing the flexural and shear capacities of RC members. However, the premature debonding of FRP laminates from the concrete substrate prior to utilizing its ultimate strength is a major concern and often results in a brittle member failure. Recent studies have indicated that adequate anchorage systems could improve the FRP-to-concrete bond and delay early debonding of the FRP laminates. The use of carbon-FRP (CFRP) splay anchors as an anchorage system is gaining wide acceptance due to its compatibility with CFRP laminates and its ability to suit a wide range of applications. However, limited studies are available in the literature that examines the effect of different anchor parameters on the laminate bond strength. Hence, this study aims to investigate the effect of different anchor parameters and configurations on the capacity of externally bonded concrete prisms with CFRP laminates. Consequently, the experimental program consisted of 30 concrete prisms that were strengthened with CFRP laminates and anchored with CFRP splay anchors. The parameters investigated were CFRP anchor diameter, embedment depth, and dowel angle. All prisms were tested in flexure under four-point bending tests. Test results showed that anchoring the laminates significantly enhanced the capacity of the prisms and FRP strain utilization compared to the unanchored strengthened prisms. In addition, varying the embedment depth and insertion angle had a significant effect on the capacity of the specimens. The strength improvement in the anchored specimens reached up to 50% over the control unanchored specimens. In addition, bond-slip models for the strengthened specimens are developed based on the obtained experimental data. The outcomes of this study will hopefully aid engineers in the design of FRP strengthened systems anchored with FRP splay anchors. It can also be concluded that CFRP splay anchors, if properly designed, could enhance the flexural capacity of RC beams by delaying the brittle debonding failure mode.College of EngineeringDepartment of Civil EngineeringMaster of Science in Civil Engineering (MSCE
On the Adoption of Circular Economy Concepts in the Manufacturing Sector
No full textA Master of Science thesis in Mechanical Engineering by Aser Alaa Fathi Elsayed Ahmed entitled, “On the Adoption of Circular Economy Concepts in the Manufacturing Sector”, submitted in November 2021. Thesis advisor is Dr. Mohammad Nazzal and thesis co-advisor is Dr. Basil Darras. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).Industrialization has brought wealth, prosperity, and abundance to many nations. However, it has had many drawbacks on people’s health and the environment. Several paradigms have been proposed and implemented in an effort to suppress and reverse the adverse impacts of human activities and industrialization. A popular approach is the circular economy (CE). CE is a waste conservative model that limits resources uptake, waste generation and energy consumption. The implementation of today’s top-notch technologies such as Industry 4.0 tools is a necessity to enable the transition from the conventional linear economy to the CE. Moreover, to ease this transition, it is important to be able to assess the circularity of different products and processes along the way. Most available assessment procedures lack comprehensiveness and objectivity due to complexities such as the quantification processes of qualitative data, the extensive use of linguistic terms that represent data and the uncertainties associated with them, and the difficulty in combining more than one indicator in case of similarity, dependency, or both. The aim of this thesis is to firstly present a thorough review on the applications of cyber-physical systems within each of the CE stages and highlight their contribution to the attainment of the different sustainable development goals through several practical examples. Secondly, it presents a comprehensive CE assessment framework that can assess the circularity of developed and developing countries, different industries, wide range of processes, and different products, of both private and public sectors on a micro, meso, and macro levels. This is achieved through a step-by-step indicators selection procedure and the combination of fuzzy logic and multi-criteria decision-making methods which deliver a CE assessment that eliminates previously mentioned problems and result in an unbiased realistic ranking of alternatives. The presented framework is implemented to assess the circularity of Friction Stir Back Extrusion against conventional extrusion methods. Results show a higher circularity score for the FSBE (48.9%) over conventional extrusion methods (4.78%), validating the applicability of the proposed CE assessment framework.College of EngineeringDepartment of Mechanical EngineeringMaster of Science in Mechanical Engineering (MSME
Microgrid Operation and Control
No full textA Master of Science thesis in Electrical Engineering by Mohammad Saad Suleiman entitled, “Microgrid Operation and Control”, submitted in April 2021. Thesis advisor is Dr. Ahmed Osman-Ahmed and thesis co-advisor is Dr. Amr Mohamed El Nady. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).The world is moving toward renewable energy resources as a result of rising energy demand and the decline of fossil fuels. This move led to the shift of interest from the centralized conventional electric grids to decentralized smart grids. Microgrid is the basic structural unit of smart grid, it can utilize both renewable and non-renewable types of distributed generator (DG) technology. As many renewable DG technologies and storage elements are based on DC power, while many loads and devices depend on AC power, the importance of inverter-based DG technology increased. The output of these inverters in an islanded microgrid must achieve a good current sharing between DG unites in microgrid, maintaining stability and synchronization between DGs, and keeping voltages and frequencies within specific range. These criteria can be achieved with various control strategies including centralized control, master slave control, current distribution control and droop control methods. Consequently, the control and operation of microgrid is a challenging task that requires overcoming the obstacles relates to the nonlinearities and disturbances in the power system. In this thesis work, two feed-back control strategies were developed and implemented in droop control to operate multiple DG units in a microgrid. The two control strategies are state feedback control and hyperbolic tangent exponential Sliding Mode Control (SMC). The developed state feedback control provided a powerful performance with respect power sharing accuracy in steady state conditions and regulating the voltage and current disturbance caused by other DG units within the same microgrid. The proposed hyperbolic tangent exponential SMC utilizes the exponential SMC method and hyperbolic tangent reaching mode to provide robust, accurate, reliable behavior against unmodeled dynamics, hard nonlinearities, and parametric uncertainties. Furthermore, an experimental set is built to imitate a microgrid operation in real life application.College of EngineeringDepartment of Electrical EngineeringMaster of Science in Electrical Engineering (MSEE
Modeling the Effects of Chemotherapy and Immunotherapy on Tumor Growth
No full textMathematical modeling has been used to simulate the interaction of chemotherapy and immunotherapy drugs intervention with the dynamics of tumor cells growth. This work studies the interaction of cells in the immune system, such as the natural killer, dendritic, and cytotoxic CD8+ T cells, with chemotherapy. Four different cases were considered in the simulation: no drug intervention, independent interventions (either chemotherapy or immunotherapy), and combined interventions of chemotherapy and immunotherapy. The system of ordinary differential equations was initially solved using the Runge-Kutta method and compared with two additional methods: the Explicit Euler and Heun’s methods. Results showed that the combined intervention is more effective compared to the other cases. In addition, when compared with Runge-Kutta, the Heun’s method presented a better accuracy than the Explicit Euler technique. The proposed mathematical model can be used as a tool to improve cancer treatments and targeted therapy.American University of SharjahSheikh Hamdan Award for Medical Science
Investigating Tensile Behavior of Sustainable Basalt–Carbon, Basalt–Steel, and Basalt–Steel-Wire Hybrid Composite Bars
No full textOne of the main disadvantages of steel bars is rebar corrosion, especially when they are exposed to aggressive environmental conditions such as marine environments. One of the suggested ways to solve this problem is to use composite bars. However, the use of these bars is ambiguous due to some weaknesses, such as low modulus of elasticity and linear behavior in the tensile tests. In this research, the effect of the hybridization process on mechanical behavior, including tensile strength, elastic modulus, and energy absorbed of composite bars, was evaluated. In addition, using basalt fibers because of their appropriate mechanical behavior, such as elastic modulus, tensile strength, durability, and high-temperature resistance, compared to glass fibers, as the main fibers in all types of composite hybrid bars, was investigated. A total of 12 hybrid composite bars were made in four different groups. Basalt and carbon T300 composite fibers, steel bars with a diameter of 6 mm, and steel wires with a diameter of 1.5 mm were used to fabricate hybrid composite bars, and vinyl ester 901 was used as the resin. The results show that, depending on composite fibers used for fabrication of hybrid composite bars, the modulus of elasticity and the tensile strength increased compared to glass-fiber-reinforced-polymer (GFRP) bars by 83% to 120% and 6% to 26%, respectively. Moreover, hybrid composite bars with basalt and steel wires witnessed higher absorbed energy compared to other types of hybrid composite bars